01 - Arrange the sliced onions and minced garlic evenly across the bottom of the slow cooker.
02 - Combine the smoked paprika, chili powder, ground cumin, salt, black pepper, and cayenne pepper in a small bowl. Rub the spice mixture thoroughly over all surfaces of the beef chuck roast.
03 - Place the seasoned roast on top of the onions and garlic in the slow cooker.
04 - Pour the barbecue sauce, beef broth, apple cider vinegar, and Worcestershire sauce evenly over the beef.
05 - Cover the slow cooker and cook on the low setting for 8 hours, or until the beef is fork-tender and pulls apart effortlessly.
06 - Transfer the beef to a large cutting board or platter. Using two forks, shred the meat, discarding any large pieces of fat or connective tissue.
07 - Return the shredded beef to the slow cooker and stir to coat evenly with the sauce. Cook for an additional 15 to 20 minutes on low to allow the flavors to absorb.
08 - Serve the pulled beef on burger buns topped with coleslaw, or over rice or in lettuce wraps for a lighter option.